1. Field
Aspects of embodiments of the present invention relate to a battery pack and an encapsulated interconnection for a battery pack.
2. Description of the Related Art
A rechargeable battery (e.g., a secondary battery) differs from a primary battery in that it is designed to be repeatedly charged and discharged, while the latter provides an irreversible conversion of chemical to electrical energy. Low-capacity rechargeable batteries are used as power supplies for, as an example, small electronic devices, such as cellular phones, notebook computers, and camcorders, while high-capacity rechargeable batteries are used as power supplies for, as an example, motors in hybrid vehicles and the like.
In general, a rechargeable battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes, a case receiving (or accommodating) the electrode assembly, and an electrode terminal electrically connected to the electrode assembly. The case may have a cylindrical or rectangular shape depending on, for example, an intended application and use of the rechargeable battery. An electrolyte solution is injected into the case to enable charging and discharging of the rechargeable battery through an electrochemical reaction of the positive electrode, the negative electrode, and the electrolyte solution.
A battery module may be formed of a plurality of battery cells (e.g., a plurality of secondary or rechargeable battery cells) connected to each other in series. The battery module may have relatively high energy density and may be used for powering the motor of a hybrid vehicle. The battery module is formed by connecting an electrode terminal of each of a number of battery cells, the number of battery cells depending on the amount of power desired, such that a high-power rechargeable battery (e.g. a high-power rechargeable battery module) may be realized.
In order to ensure safe operation of such battery modules, heat generated by the rechargeable batteries (e.g., generated by the battery cells) should be efficiently emitted, discharged, and/or dissipated therefrom. If there is insufficient heat emission/discharge/dissipation, a temperature deviation occurs between the battery cells such that the battery module cannot generate the desired amount of power. In addition, when the internal temperature of the battery cells increases (e.g., increases due to the heat generated thereby), abnormal reactions occur in the battery cells such that charging and discharging performance of the rechargeable batteries deteriorates and the life-span of the rechargeable batteries is reduced.
Cooling devices for cooling the rechargeable battery modules by efficiently emitting/discharging/dissipating heat generated by the battery cells are generally understood. The cooling device should be in thermal contact with a surface of the battery module (e.g., in contact with a surface of the battery cells). The cooling device may be constructed as separate device and attached to the surface of the battery module or may be integrated in a housing of the battery module.
To further increase the energy density of battery systems, for example, in order to increase a driving range of electric vehicles, a plurality of battery modules may be stacked and electrically interconnected to form a battery pack. In order to ensure sufficient emission/discharge/dissipation of the heat generated by the battery modules of the battery pack, such multi-level battery packs may include a cooling device for each layer of the battery pack (e.g., for each level of battery modules in the battery pack).
The structures for distributing coolant to a plurality of battery modules are generally weak points of the battery pack in terms of mechanical stability and rigidity, both during normal use and in a crash situation. In addition, depending on the type of secondary battery included in the battery modules, for example, a lithium ion battery, and the type of used coolant, for example, water-based coolants, leaking coolant may severely damage the battery modules and even surrounding structures, for example, surrounding structures in an electric vehicle.